Describe the process of osmosis

Osmosis is the movement of water molecules from a high partial pressure (or concentration) to a low partial pressure (or concentration) down a partial pressure (concentration) gradient. 

For example, think of a cell. On the outside of the cell mebrane there are lots of water molecules, lets say 10. On the inside of the cell there are only 3 water molecules. Where lots of water molecules are present there is a high partial pressure. Where only 3 water molecules are present there is a low partial pressure. 

Therefore, since osmosis is defined as the movement of water molecules from a high partial pressure to a low partial pressure, water will move from the high partial pressure outside the cell, into the cell where there is a low partial pressure, down a concentration gradient. 

The words and phrases I have higlighted in bold are really key to put into your answer as this is where you will get marks!

Do you have an questions or would you like me to explain it differently?